Held K Gerrit, Jaeger Michael, Rička Jaro, Frenz Martin, Akarçay H Günhan
University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
Photoacoustics. 2016 Jun 4;4(2):70-80. doi: 10.1016/j.pacs.2016.05.004. eCollection 2016 Jun.
Spectral optoacoustic (OA) imaging enables spatially-resolved measurement of blood oxygenation levels, based on the distinct optical absorption spectra of oxygenated and de-oxygenated blood. Wavelength-dependent optical attenuation in the bulk tissue, however, distorts the acquired OA spectrum and thus makes quantitative oxygenation measurements challenging. We demonstrate a correction for this spectral distortion without requiring knowledge of the tissue optical properties, using the concept of multiple irradiation sensing: recording the OA signal amplitude of an absorbing structure ( blood vessel), which serves as an intrinsic fluence detector, as function of irradiation position. This permits the reconstruction of the bulk effective optical attenuation coefficient . If performed at various irradiation wavelengths, a correction for the wavelength-dependent fluence attenuation is achieved, revealing accurate spectral information on the absorbing structures. Phantom studies were performed to show the potential of this technique for handheld clinical combined OA and ultrasound imaging.
光谱光声（OA）成像能够基于氧合血红蛋白和脱氧血红蛋白不同的光学吸收光谱，对血氧水平进行空间分辨测量。然而，大块组织中与波长相关的光学衰减会使采集到的OA光谱发生畸变，从而使定量血氧测量具有挑战性。我们利用多重照射传感的概念，演示了一种无需了解组织光学特性即可校正这种光谱畸变的方法：记录作为本征通量探测器的吸收结构（血管）的OA信号幅度随照射位置的变化。这使得能够重建大块组织的有效光学衰减系数。如果在不同的照射波长下进行测量，就可以实现对与波长相关的通量衰减的校正，从而揭示吸收结构的准确光谱信息。进行了体模研究，以展示该技术在手持式临床联合OA和超声成像中的潜力。
